illustrated by the temperature variation in the little idyllic village of Målilla in the county of Småland in southern Sweden, for which data are available from the Swedish Institute of Meteorology SMHI since 1860. Målilla has the Swedish record high of 38 degrees Celcius from 1948, before global warming was invented...

We see, as we all know, that the daily temperature can only be predicted a couple of days ahead, to a meaningful tolerance, while the monthly or even better yearly mean-value can be predicted years ahead to a meaningful tolerance.

We are thus pleased to see that our book, written before we lifted our horizon to climate dynamics, directly connects to the crucial question of accuracy and reliability of climate models. We see these connections in particular in the recent text by HK Climate.

2 kommentarer:

Your first three paragraphs are perfectly correct. Your fourth, "These are also the features of climate dynamics, which is also a form of weather dynamics only on larger space-time scales" is wrong.

You have already conceded that chaotic dynamics are "long-time mean-value predictable". We define climate prediction precisely as the prediction of such predictable long term statistics.

(There is a discipline of predicting two month to eighteen month prognostics that calls itself "climate prediction" that is essentially weather prediction of the slower dynamics of the ocean. It is dominated by heuristics and has demonstrated very limited value at best. If your criticism is with this field I agree with you. Indeed some of the most vocal IPCC critics like Gray and Landsea come from this tradition. But this is NOT the sort of climate prediction taht the controversy is about.)

The decadal to millenial time scale falls neatly into the class of in-principle-predictable statistics. Whether the predictions are useful in practice is another matter, but that is, you will acknowledge, an entirely different argument.

Regardless, it is clear that anthropogenic forcing must have SOME impact on the dynamics. Are you saying it is impossible to apply reason to any extent whatsoever about such impacts?

If so, if the available information about the impact of emissions really is absolutely nil, then the risk of substantial alteration of the atmosphere is unbounded and the rational policy is to avoid such alteration with the most extreme rigor.

Normally people arguing against climate science oppose regulation of emissions, but this has always seemed to me logically inconsistent. I expect it from politicians and journalists, but not scientists.